Conventionally, the brake control apparatuses having a variety of configurations for controlling the braking force applied to the wheel of the vehicle are suggested. For example, patent document 1 discloses the brake control apparatus, which increases a degree of freedom of fluid pressure control in wheel cylinders of four wheels according to a condition to control the braking force. This device includes a power fluid pressure source capable of accumulating a pressure by operating fluid by using power and a manual fluid pressure source, which pressurizes the operating fluid according to a brake operational amount by a driver, and is configured to be able to control a fluid pressure in the wheel cylinder by each fluid pressure source. A fluid pressure route, which controls a left front wheel, a right front wheel, a left rear wheel, and a right rear wheel in common, is connected to the power fluid pressure source to control to pressurize the wheel cylinders of the four wheels at the time of normal control. The brake control apparatus is a regeneration cooperative brake control apparatus, which improves fuel consumption performance of the vehicle by utilizing regenerative braking force.
Also, patent document 2 discloses the brake control apparatus including the power fluid pressure source and the manual fluid pressure source. In this device, a fluid pressure flow channel for the front wheel and the fluid pressure flow channel for the rear wheel are connected to the manual fluid pressure source and braking control only by the front wheel or the rear wheel may be performed by the manual fluid pressure source.
Recently, the vehicles have a tendency to place much value on ride quality and it is desired to design a fluid pressure circuit capable of executing smooth braking regardless of technique and habit of the driver at the time of braking. In response to this demand, in a case of the conventional brake control apparatus, a pressure increasing linear control valve configured to adjust to increase a fluid pressure from a fluid pressure source and a pressure reducing linear control valve configured to adjust to reduce the same are provided such that the braking force may be finely controlled to be increased or reduced regardless of operation of a brake pedal. Also, in a case of the regeneration cooperative brake control apparatus of patent document 1, it is configured such that the vehicle is braked by distributing required braking force required by the driver at a predetermined distribution ratio by frictional braking force generated by operation of the wheel cylinder and the regenerative braking force generated by regeneration. However, since the regenerative braking force generated by the regeneration always changes according to a travel state of the vehicle, a charge state of a battery and the like, the fine control to increase or decrease the frictional braking force regardless of the operation of the brake pedal is required when the required braking force required by the driver is to be ensured. That is to say, the pressure increasing linear control valve and the pressure reducing linear control valve are required.